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ToolWrenEstimate your monthly mortgage repayment, total interest and total cost. Enter the property price, deposit, interest rate and term — add tax and insurance for a full picture.
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Mortgage is a free, private online tool that lets you free mortgage calculator: work out your monthly repayment, total interest and total cost from the property price, deposit, interest rate and term, with optional property tax and insurance. It runs entirely in your browser, so nothing you enter is uploaded to a server.
Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.
From the property price, your deposit (as an amount or a percentage), the interest rate and the term, the calculator works out your monthly principal-and-interest payment, the loan amount, the total interest you will pay, the total of all payments and the payoff date.
Type your deposit as a cash amount or as a percentage of the price — the two fields stay in sync automatically, so you can plan around a 10%, 15% or 20% deposit without doing the maths yourself.
Expand the extra section to add annual property tax and home insurance, and the tool shows your true monthly outgoing including those costs, not just the loan repayment.
A mortgage calculator turns the four numbers everyone knows - property price, deposit, interest rate and term - into the numbers that actually matter: your monthly payment, the total interest you will pay over the life of the loan, the total cost, and the date the mortgage is paid off. Seeing all of these together makes it far easier to compare deals and understand what you can really afford.
Mortgages use amortisation: each monthly payment is the same, but early on most of it is interest and only a little pays down the balance, while later the balance falls faster. The payment is calculated with the standard formula M = P × r × (1+r)^N ÷ ((1+r)^N − 1), where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12) and N is the number of monthly payments (years × 12). This tool applies that formula exactly, and handles the 0% edge case by simply dividing the loan by the number of months.
Your deposit is subtracted from the price to give the amount you actually borrow, so a bigger deposit shrinks both the monthly payment and the total interest - often dramatically. Because deposits are quoted both ways, this calculator lets you enter a cash amount or a percentage and keeps the two in sync, so you can instantly see what a 10%, 15% or 20% deposit means in real money and in monthly cost.
Two things drive the total interest: the rate and the term. A lower rate obviously helps, but the term is just as powerful - a longer term lowers the monthly payment yet increases the total interest substantially, because you are borrowing for longer. The calculator shows total interest and total repaid alongside the monthly figure precisely so you can weigh a comfortable monthly payment against the lifetime cost.
The headline mortgage payment is only principal and interest, but your real monthly housing cost usually includes property tax and home insurance (and sometimes mortgage insurance or service charges). Add annual tax and insurance figures in the optional section and the tool shows your full monthly outgoing. Remember this is an estimate to help you plan - it is not financial advice, and a lender's official quote may differ. Everything is calculated in your browser, so your financial details are never uploaded.